Reproducible failure TestOrdinalMap.testRamBytesUsed

[easyice]

Description

bisect shows 55ca9f7 is the first bad commit

   >     java.lang.AssertionError: expected:<976> but was:<960>
   >         at __randomizedtesting.SeedInfo.seed([55680AD930225FC5:A7CB1899FA5D4093]:0)
   >         at org.junit.Assert.fail(Assert.java:89)
   >         at org.junit.Assert.failNotEquals(Assert.java:835)
   >         at org.junit.Assert.assertEquals(Assert.java:647)
   >         at org.junit.Assert.assertEquals(Assert.java:633)
   >         at org.apache.lucene.index.TestOrdinalMap.testRamBytesUsed(TestOrdinalMap.java:102)
   >         at java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:103)

Gradle command to reproduce

./gradlew :lucene:core:test --tests "org.apache.lucene.index.TestOrdinalMap.testRamBytesUsed"  -Ptests.seed=55680AD930225FC5 -Ptests.nightly=true